dev-implementation

# Dev Implementation Run implementation work for configured AI docs features. Before changing docs or code, propose the concrete plan for this phase and wait for user approval unless the user already approved the exact phase plan. ## Phase Contract 1. Run `npx ai-devkit@latest lint` before phase work. 2. If working on a named feature, run `npx ai-devkit@latest lint --feature <name>`. 3. Read requirements, design, planning, implementation, and testing docs before changes. 4. Use the `tdd` skill while executing implementation tasks: write a failing test before production code, then make it pass. 5. Apply the `verify` skill before completing tasks or making implementation alignment claims. 6. Keep testing and implementation docs in lockstep with code. Do not defer all doc updates to final verification. 7. If parent `dev-lifecycle` established usable task tracing, emit phase, progress, next-step, blocker, and evidence events per `task`. ## Execute Plan Use for Phase 5. 1. Run `npx ai-devkit@latest lint --feature <name>` and work through the planning doc path it validates. If manual path resolution is unavoidable, first resolve `.ai-devkit.json` `paths.docs`, falling back to `docs/ai`. 2. Gather context: feature name, planning doc path, supporting docs, current branch, and current diff. 3. Parse task lists and build an ordered queue by section. 4. Present the task queue with status: `todo`, `in-progress`, `done`, `blocked`. 5. For each task, show context, suggest relevant do...